Delta Aurigae

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Template:Short description

Delta Aurigae
Template:Location mark
Location of δ Aurigae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 3.715[2]
Characteristics
Evolutionary stage red clump[3]
Spectral type K0 IIIb[4]
U−B Template:Engvar +0.837[2]
B−V Template:Engvar +1.017[2]
R−I Template:Engvar 0.5
Astrometry
Radial velocity (Rv)Template:Val[5] km/s
Proper motion (μ) RA: +85.814[1] mas/yr
Dec.: −142.928[1] mas/yr
Parallax (π)23.0557±0.4512 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)0.56[6]
Orbit[7]
Period (P)Template:Val
Semi-major axis (a)≥ Template:Convert
Eccentricity (e)Template:Val
Periastron epoch (T)Template:Val
Argument of periastron (ω)
(secondary)
Template:Val°
Semi-amplitude (K1)
(primary)
Template:Val km/s
Details
Mass1.63[8] Template:Solar mass
Radius11[9] Template:Solar radius
Luminosity62[9] Template:Solar luminosity
Surface gravity (log g)2.7[9] cgs
Temperature4,786[9] K
Metallicity [Fe/H]−0.15[9] dex
Rotational velocity (v sin i)3.9[9] km/s
Age3.26[8] Gyr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[10]
Database references
SIMBADdata

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Delta Aurigae is an astrometric binary[11] star in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from δ Aurigae, and abbreviated Delta Aur or δ Aur. This star is visible to the naked eye with an apparent visual magnitude of 3.715.[2] Based upon its annual parallax shift of Template:Val,[1] it is some Template:Convert distant from the Earth, give or take a three light-year margin of error. It is drifting further away with a radial velocity of +10 km/s.[5] This star is the namesake for the Delta Aurigids, a meteor shower that occurs between October 6–15.[12] The radiant point for this shower passes several degrees to the south of the star.[13]

The variable radial velocity of this system was not recognized until 1999, more than a century following the first measurement in 1897. Delta Aurigae is a single-lined spectroscopic binary: periodic Doppler shifts in the star's spectrum indicate orbital motion. The pair have an orbital period of Template:Convert and an eccentricity of 0.231. Based on the small amplitude of the radial velocity variation, the companion is most likely a small K- or early M-type main-sequence star with around half the mass of the Sun.[7]

The visible component of this system is an evolved giant star with a stellar classification of K0 IIIb.[4] It is a red clump star, indicating that it is generating energy through helium fusion at its core.[3] This star is 3.26[8] billion years old and is spinning with a projected rotational velocity of 4 km/s.[9] It has 1.63[8] times the mass of the Sun and has expanded to 11[9] times the Sun's radius. The star is radiating 62 times the Sun's luminosity[9] from the star's photosphere at an effective temperature of 4,786 K.[9] This heat gives the star the orange-hued glow of a K-type star.[14]

Name

In Indian astronomy, it is known by the name Prajapati Template:IPAc-en, from the Sanskrit प्रजापति prajāpati "the Lord of Created Beings".[15][16]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Eight Kinds of Crops, refers to an asterism consisting of δ Aurigae, ξ Aurigae, 26 Camelopardalis, 14 Camelopardalis, 7 Camelopardalis, 9 Aurigae, 11 Camelopardalis and 31 Camelopardalis.[17] Consequently, the Chinese name for δ Aurigae itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx), refers to the rice.

References

Template:Reflist

External links

Template:Stars of Auriga

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  3. a b Cite error: Invalid <ref> tag; no text was provided for refs named Alves2000
  4. a b Cite error: Invalid <ref> tag; no text was provided for refs named Keenan_McNeil_1989
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  8. a b c d Cite error: Invalid <ref> tag; no text was provided for refs named Luck2015
  9. a b c d e f g h i j Cite error: Invalid <ref> tag; no text was provided for refs named aj135_1_209
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  14. Cite error: Invalid <ref> tag; no text was provided for refs named csiro
  15. "Auriga", by Richard Hinckley Allen in Star Names: Their Lore and Meaning
  16. Monier-Williams Sanskrit dictionary: pra-cchana—pra-jalpa
  17. Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.